31 CAD in Textile Designing

R. Sheela John

Computers play a significant role in the textile industry. Textile industry of India contributes a major share to the economy though it’s domestic and export market. It is one of the fastest growing segments and hence calls for use of latest technology. And the use of CAD improves the quality and quantity of production and provides the consumer with new fabric and garment designs.

Learning Outcome

Gain knowledge about significance of CAD in designing

Learn the significant applications of CAD in Weaving, Knitting, Printing and Embroidery
CAD designing has become more common because of its easy accessibility. It is easy to learn, interesting and heartening to create new unique designs. The application of CAD in textile designing are discussed under the following heads
CAD in designing CAD in Weaving CAD in Knitting
CAD in Printing and CAD in Embroidery

CAD in Designing

The Computer Aided Designing increases the productivity of the designer, improves the quality of the design, creates database for manufacturing and improves documentation. In general terms CAD means computer assistance whilst a designer converts his or her ideas and knowledge into a mathematical and graphical model represented in a computer. CAD systems help in design, constructing and modelling of garments with rapidity and extra accuracy. The designing of garments in the CAD software has the following advantages

Tools – Pen of different types and sizes are available to the artist. This enables the artists to draw lines of different shapes and sizes. The shapes of the lines can be easily modified without erasing them.
Colours and brushes – the CAD offers a wide range of colours, maybe a million shades. Also the artists has the freedom to choose from different colour wheels for example – RGB, CMYK etc., The range of brushes and sizes is a boon to the designer. It is very difficult to create a spray painting effect which can be easily created in the computer
Effects – The CAD provides the designer with a variety of images, fabric designs which will take days to draw manually. Fabric swatches (new fashion fabrics) can be scanned or photographed into the image library and draped on the sketch in few minutes.
Editing – the copy and paste options helps in recreating the designs in part or full in colour helps in repeating the motifs. The number of repeats of the motif and the size of the motifs can be controlled by scaling techniques. Mirroring the image and erasing or deleting part of the design is made easy with the advent of computers. The designs undergo changes many times, still the designs sheets can be maintained clean. The erasing tool and delete tool does the work without soiling the paper. Crop tool also helps in taking the part of the design easily.
Storage of designs – The garment designs can be stored in the computer memory and a copy of it can be stored in the CD or pen drive and the same can be retrieved anytime, anywhere. The paper on which the design is drawn may get spoiled after a period time. Thanks to the computer the designs can be stored unlimited time duration. The designer can work half way through the design and store it the system and work after whenever he feels comfortable without much stress
Zoom tool – By using the ‘Zoom’ and ‘Pan’ tool the design parts can be enlarged and the details can be observed and edited accurately.
Physical arrangement – the designer usually needs an easel board, and a stand for keeping different types of pen, pencils, colours and palette. With CAD the artist needs only a system to draw and paint the fashion sketches
Internet – the Designs can be stored in the email and can be retrieved in any place of the world. The burden of carrying the paper and maintaining the design is eliminated. The designer can send the designs to foreign countries for approval with the touch of a button
Hence the CAD design aids the designer in creating designer faster and neat. It also enhances the creativity of the designer.

The designing in the CAD includes garment designing, textile designing (weaves, knits and prints) and embroidery designs

CAD in Textile Designing

Much of the use of CAD grew from the idea that new textiles could be created by scanning existing designs and making modifications. Most of the first systems were used in their manner. Textile designs include designs created with weaving, knitting and printing.

CAD in Knitting

Knitting is a method of fabric formation where the yarns are interlooped. The knitted fabric can be created in the flat bed machine or circular knitting machine. The recent developments in knitting include seamless garments.

Knitting systems allow users to divide illustrations into grids that indicate each stitch and then to specify the structure of the resulting pattern, mixing the combination of coloured yarns and different stitch formations. Some give a realistic visualisation of the finished effect on screen, allowing designers to make changes before samples are produced. All have the ability to produce the output on tape, disc or by direct connection to knitting machinery so the production of the design is quick. Designs can be then passed onto production in ready-to-use form.

CAD systems are used for two main purposes – one to define on a grid format the layout of yarns and stitch formations that will be used to create a final item. In this form CAD is the primary means by which a design is turned into a fabric. The other purpose is to produce realistic images that represent the finished product.Output from systems takes two forms; predominantly systems are used to produce instructions for knitting machinery on disk or directly to a printer. The alternate form of output is a colour printer. The knitted fabric can be simulated on a body from and shown as a garment

Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) have revolutionized the knitting industry. The 1970s saw the introduction of CAD/CAM systems. Designers used the CAD system to create product designs and these were transferred to CAM machines to manufacture the final product. CAD/CAM technology replaced the mechanical patterning and shaping devices on machines with electronic controls. These systems enabled companies to respond quickly to changes in demand. New designs could be set up using CAD and quickly produced on the CAM machine. Though manually operated flat and V-bed knitting machines are still used, computerized technology is also preferred. Initially, this system was expensive and only the major companies could afford it. However, in the 1980s and 1990s CAD/CAM fell in price and even the small and medium sized companies invested in this new technology. The introduction of this technology enabled companies to work globally, and on a fast scale.

Side by side with the CAD/CAM knitting technology, the process of whole garment knitting was introduced. Cutting fabric into shapes and then stitching the pieces together to create garments has been in practice since the eighteenth century. In the 1970s companies researched more efficient technologies which could produce a complete garment in one process without the need for sewing. Without the loss of fabric associated with cut and sew techniques, garments could be knitted quickly.

CAD in Weaving

Weaving is a method of fabric construction where a warp yarns and weft yarns are interlaced at right angles. The interlacement of the yarns, the structure of the yarns and the colour of the yarns can be varied. There is a lot of variations in the weave patterns. The yarn is woven into a fabric in a loom. The yarn is spun from the fibers and the preparation of the yarns on the loom is an elaborate process. Lots of calculations are involved at every stage. CAD is an indispensable tool to a yarn/fabric designer. The following points proves the above said statement.

It improves the creativity of the designer.
A new sample can be scanned and the same can be digitised and converted into an weave pattern.
The software has inbuilt facilities of yarns of different varieties. Hence a yarn of the desired quality and dimension can be selected.
The weave patterns can be changed easily. Input of weave patterns automatically aids in the creation of draft plan and peg plan.
The computer has a wide range of colours. Designer has the freedom to select from thousands of million colours.
The effects / patterns / design availability can be easily created. The spray patterns that takes days for a designer to manually draw can be created in a matter of a few minutes or even seconds.
The duplication of designs and editing of designs is faster and neat. The designs can be cropped at any portions and mirrored or rotated at any angles and the same can be saved in another file. The editing does not create any damage or spoil to the paper.
The pattern generator automatically generates the pattern / fabric design on the screen which helps the designer to gain a clear perspective.
It takes weeks for the designer to view the fabric sample. As the spinning of the yarn and the weaving of the fabric takes a longer time. Thanks to the CAD, the design can be rendered and the final appearance of the fabric can be viewed instantly.
The design can be viewed in different colours which enables the mills to sell the fabric without creation of sample which is a very costly process. This gives more choice for the buyer.
Recent technology is a boon to the garment / textile industry where the fabric can be draped onto a 3D model.
The fabric simulation, the draping of the fabric in the garment on a model and the change of the colours thus enhances the marketing of the fabric.
The samples can be presented in the digital form to the buyer and hence the task of carrying of bulks of samples and maintaining the samples for long distances can be eliminated.
The approval of the fabric swatches for an export order can be done by mailing the same in the web.
The production details like the weight of the yarn, length of the yarn and the loom card details can be generated automatically. This helps in eliminating the complicated job of minute calculations like the yarn needed for the floats, crimp etc.,
The production data’s can be directly taken to the loom for production
A printer to see the output of the design in a miniature size. The plotters is a large scale printer that will give the final appearance of the design in its original size.

CAD in Printing

The main uses of CAD system are the creation of original designs, or the interpretation of artwork supplied by customers, the latter being either painted artwork, fabric samples or possibly black and white film negatives. The following is the list of advantages of digital textile printing:

Permits customers to control the design and printing process from remote locations.
Virtually eliminates the expense and time of screen printing preparation.
Makes Just in Time (JIT) delivery and the Quick Response is also possible.
Can virtually eliminate the threat of design theft before market release.
Facilitates the increase in the number of fashion seasons.
Prints directly from easily stored, transmitted, and transported computer files.
Reduces the space necessary for archiving art, films, plates, and screens.
Is more cost effective for proof and short-run printing than analog printing methods.
Reduces proofing time from weeks to hours, thus accelerating design and product development.
Permits customization and personalization. Allows for design correction and modification at any time without significant schedule delays or cost increases.
Eliminates the design and process distortions associated with on-contact analog printing.
Is cleaner, safer, and generally less wasteful, and less environmentally hazardous than analog textile printing methods.
It has been established that, thanks to digital printing technology, designers can now reduce textile research and pattern design time by over 50%.
The designer can now see how a particular piece of fabric or garment will look in different colours and shapes without having to commit to a final product.
On the basis of above advantages we can say that the changeover from traditional design work to using a CAD system can be a very positive experience.

Creation of designs: The designs can be created virtually in the computer using the different type of pen, paint brushes and effects. Usually a motif is created first and is repeated to the length of the fabric. Software packages now have a wide range of effects such as water colour and oil which enable different results to be created with the same input devices. The next step is to repeating the pattern. The use of clone brushes is helpful in the blending of wash effect and backgrounds into the new areas of the design or the artist can draw new motifs to complete the repeat. Following this, is the cleaning up of individual images or motifs. Here we use a combination of reduce brushes, dot clear brushes, dot removal and drawing function. It is easier to work on the CAD systems where the manipulation of the design/ motif is very easy. Any kind of repeat like straight, half drop, mirror, with or without overlap can be chosen. The motif can be rotated to any angle, mirrored, copied and pasted any number of times at the click of a button. The size of the design can also be scaled. Design by can be enhanced by shading any texture over the design which produces realistic fabric renderings. Designs that are stored in the system can be retrieved and edited by cropping a portion of the design or adding details to it. The colour of the design can be changed any number of time before finalising it. The storage of the design is easy and does not require a large space as that of the manual designing.

Scanning artwork: Textile design systems sometimes start with work created on paper or other medium. Most companies making printed textiles use scanners to capture data in digital form. Scanner can also be used to scan in black and white, artwork and separates. We can also scan black and white film, and then merge them back into a coloured design in our design station. Of course, the great advantage is that a user can undo any element so that mistakes or unwanted effects can instantly be corrected. Other systems use digital cameras as a means of data capture.

The editing of designs: The first step in editing a design is to take the scan file and do some colour reduction to get the file as close as possible to the final number of colours that the finished design will have. Some of this will be done by the colour reduction function in the CAD system, where the computer picks the next closest colour left in the palette to replace the colour to be discarded, or we choose which colour we want to replace the colour being discarded. We then use CAD systems to manipulate the image, changing colours, adding, deleting, moving or copying elements and putting them overall into a suitable pattern repeat

CAD in Embroidery

Embroidery is a surface decoration applied in a fabric / garment to add value to the product. Traditionally embroidery is made in hand. It involves artisans with artistic skills and it takes a longer time to complete. Later the embroidery machines were developed which contains the set number of stitches which can be varied in length and width.This reduces the time of production, but it still calls for skill on the part of the embroiderer. With computerised embroidery machine the commercial production is made easier and cheaper. It can embroider upto 12 samples at a time and it takes only a few minutes for the design to be embroidered. The following are the steps involved in the computerised embroidery machines for creating embroidery design

Creation of embroidery design
Loading the embroidery design in the machine
Positioning the fabric in the machine
Embroidering the design

Creation of embroidery design – Designs for the embroidery can be created in any one of the following ways

Designs commercially available can be purchased to suit the machine.
Manual designs can be transferred into the system through the digitiser. In other words, the manual designs can be digitised with the help of a digitiser
Designs can be created in the system usingappropriate software.
CAD allows the designer to crop, scale, rotate, move, copy, paste, stretch or distort the designs

Texts can be added in the desired font and size. Many colour schemes can be created from which a final design can be selected. The designs thus created should be in the machine format, if not has to be converted into the machine formats.

Loading the embroidery designs – Different machines require different formats. The most common home design format is PES. Other design file formats are ART, PES, VIP, JEF, SEW and HUS. Embroidery patterns can be transferred to the computerized embroidery machines through cables, CDs, floppy disks, USB interfaces, or special cards that resemble flash or compact cards.

Positioning the fabric – The embroidering a fabric is placed in a frame. This offers stability to the fabric. Certain types of fabrics require stabiliser to keep the fabric firm. These stabilisers are backup fabrics laid under the fabric or on top of the fabric. Stabilizer types include cut-away, tear-away, vinyl, nylon, water-soluble, heat-n-gone, peel and stick, and open mesh.

Embroidering the design –Embroidery is done with the embroidery head and thenumber of heads in a machine varies from one to fifty six. After the fabric is hooped it is fixed to the machine. The machine is threaded with embroidery threads of prescribed colour. Some machines may have single needed and some may have multi needles. Once the machine is switched on, all the machine heads starts to stitch the designs at the same time and the process needs only monitoring.

Advantages of computerised embroidery machines are

Designs can be made faster and easier.
It can be stored for a longer time and can be reused whenever needed. The space needed for physical storage can be eliminated.
Thick and thin fabrics can be embroidered with ease. Stitch speed and capacity can be increased.
Special applications like applique, quilting and sequence work are additional features. The quality of stitching is very high and is ideal for commercial use.

Conclusion

Today’s fashion business calls for unique designs, high quality, less cost, quick response and immediate supply of fabrics and garments. There is also an increase demand for new fabric and garment designs which necessitates the use of CAD and CAM. This technological development helps to create fabrics/ garments with good quality and greater quantities either with weave or knit or weave or embroidery designs. A sound knowledge of CAD helps the designer to be more successful in the field of fashion

you can view video on CAD in Textile Designing

Books

Computers in the Garment Industry – Dr R Sheela John and Dr S Amsamani
Fashion Production Terms – Debbie Ann Gioello and Beverly Berke
The technology of clothing manufacture – Harold Carr and Barbara Latham